How to get a serial console log on the TsP

Many Bufalo's devices need some soldering work to get the console output over the serial link, the good news with the TeraStation Pro is that you don't even need to open the box to get serial console access because you can use the UPS serial port ! The "bad" news is that you need to start the TsP at least one time to switch the serial link from UPS function to serial function.
There are 2 methods to switch the serial link to console mode :